There is a growing demand for sound recognition and sound analysis, so that a technology is desired by which a sound that a speaker has uttered is accurately analyzed. As a technology of the sound analysis, there is a method called binary masking. In the binary masking, frequency analysis is performed on sounds obtained through a plurality of input devices, and the sizes of signal levels are compared with each other for each frequency component, and the input of a target sound having a large signal level and the input of a non-target sound having a small signal level are identified, and the non-target sound is removed to perform analysis of the target sound. Japanese Laid-open Patent Publication No. 2009-20471 is the related art.